1. Field of the Invention
This invention is generally directed to trailer hitches for vehicles and more specifically to fifth wheel trailer hitches utilized on the cargo beds of vehicles and particularly conventional pickup truck beds. The fifth wheel trailer hitch assemblies of the present invention include a hitch ball which is mounted to a base that is selectively secured within a sleeve which is mounted so as to extend through the bed of the vehicle with the sleeve being reinforced by supports which are secured beneath the bed of the vehicle. The base portion of the hitch ball includes side openings therethrough which are selectively aligned with side openings through the sleeve member so that a locking pin may be selectively aligned and extended therethrough to thereby secure the hitch ball in fixed relationship with respect to the retention sleeve so that the hitch ball extends above the bed of the vehicle. The locking pin may be selectively manually withdrawn from engagement with the base portion of the hitch ball and the retention sleeve to permit the removal of the hitch ball so that the hitch ball may be raised and inverted and re-inserted within the sleeve member The sleeve member includes a lower wall which includes an enlarged opening therein which permits the passage of the hitch ball when inserted in the inverted position. When the side openings through the base portion of the hitch ball and the sleeve member are appropriately aligned, the locking pin may be re-inserted therethrough thereby locking the hitch ball in an inverted position wherein the lowermost surface of the base thereof is substantially flush with the cargo bed of the vehicle so that the cargo bed may be utilized in a conventional manner without any interference or obstruction by the hitch assembly.
2. History of the Related Art
Conventional trailer hitches for light weight automobile and truck type vehicles normally include a hitch plate or bar which is welded adjacent the rear bumper of the vehicle or on the rear bumper of the vehicle and to which a hitch ball may be selectively secured. There are a number of conventional sizes of hitch balls which may be utilized depending upon the hitch assembly which is incorporated with the trailer that is to be towed. One shortcoming in such conventional rear end hitch assemblies is that the amount of weight which may be pulled by the vehicle is limited as the weight or force placed on the hitch assembly is at a point which is spaced from the rear axle of the vehicle. With this type of assembly, an increased moment of force is enduced about the rear axle thereby limiting the load which may be safely pulled by the vehicle without adversely effecting the weight distribution to the front wheels of the vehicle.
In order to overcome the foregoing problem, a system for mounting trailer hitches was developed which has been referred to as a "fifth wheel" type trailer hitch. The fifth wheel trailer hitch includes a hitch ball which is mounted over or slightly forwardly of the rear axle of a flat bed type vehicle and particularly pickup trucks. By positioning the hitch ball above or forwardly of the rear axle of the vehicle, the weight which the vehicle can tow is significantly increased over vehicles having the rear end type hitch assemblies. In order to allow the trailing vehicle to be connected to a fifth wheel type hitch, a "gooseneck" type extension is utilized on the towing arm of the trailing vehicle. The gooseneck is generally somewhat curved with the hitch portion being disposed at the forward end thereof and with the central portion thereof extending upwardly and over the rear of the pulling vehicle.
Although the fifth wheel trailer hitch assemblies provide the added advantage of allowing a vehicle to safely tow a greater weight load, the placement of the trailer hitch ball along the cargo bed of the towing vehicle adversely effected the normal use of the cargo bed when the vehicle is not being utilized to pull a trailer. In order to overcome this disadvantage, there have been a number of structures developed for allowing the trailer hitch ball to be either selectively removed or retracted from its use position relative to the cargo bed of the towing vehicle.
In U.S. Pat. No. 4,546,994 to Taylor, a universal trailer hitch of the fifth wheel type is disclosed which includes a reinforcing frame which is mounted beneath the cargo bed of the towing vehicle. The frame supports a reinforcing bed plate to which is secured a trailer hitch support sleeve which extends vertically therefrom. The support sleeve is open so as to selectively receive the base or post of a trailer hitch ball that may be selectively positioned therein so that the hitch ball is elevated with respect to the cargo bed of the towing vehicle. The size of the hitch ball may be selectively altered by utilizing different sizes of ball elements with the hitch assemblies. When the hitch ball is in use, a locking mechanism is provided which includes a pin member which is selectively extendable through the hitch support sleeve and the post of the hitch ball assembly. When the hitch ball is not in use, it is selectively removed from the support sleeve and stored in a remote location. This leaves the opening in the support sleeve exposed through the bed of the vehicle and also requires that the hitch ball assembly be placed in another location in the vehicle or stored in a place remote from the vehicle when not in use.
Due to the inconvenience which is associated with having to remotely store a hitch ball assembly when not in use, other fifth wheel trailer hitch assemblies have been developed wherein the hitch ball is mounted so as to be retained beneath the cargo bed of the vehicle when not in use. In U.S. Pat. No. 4,657,274 to Mann, et al, a retractable king pin assembly or hitch assembly for the bed of a vehicle is disclosed which incorporates a king pin or hitch ball which is mounted on an elongated shaft which is provided with a vertical rack assembly having teeth which are selectively engageable with a gear that may be manually rotatably operable so as to extend or retract the hitch ball vertically relative to the cargo bed of the vehicle. When the hitch ball is in a fully retracted position with respect to a guide sleeve through which the gear extends so as to contact the vertical rack assembly associated with the hitch pin, a pair of plate members are hingedly connected to the vehicle bed and are moveable into a flat configuration covering the opening in the area of the hitch assembly.
In U.S. Pat. No. 4,570,966 to Giboney, et al, a retractable trailer hitch ball assembly is disclosed which includes a housing which is mounted beneath the vehicle load bed and which incorporates a hitch ball element that is selectively extended through an opening in the housing upwardly through an opening in the bed of the vehicle. The hitch ball is extended by operation of a hydraulic cylinder which is operable from controls disposed in the cab of the vehicle. The hitch ball is carried by a pivotable plate which is normally urged into a retracted position so that the hitch ball is moved inwardly of the housing when not in use. The pivotable plate assembly is operable by the hydraulic cylinder arm which acts to urge the plate upwardly relative to the vehicle bed to thereby extend the hitch ball to a use position. Another retractable fifth wheel trailer hitch assembly is disclosed in U.S. Pat. No. 4,256,324 to Hamilton. In this patent, the trailer hitch ball is pivotably mounted to a housing which is installed through an opening in the load bed of the vehicle. The housing further incorporates a second pivotable plate member which forms an extended portion of the vehicle load bed when the ball is in a use position and which is pivotable upwardly relative to the hitch ball so as to allow the hitch ball to rotate about its mounting axis to a position beneath the bed of the vehicle. The side portion of the base of the hitch ball forms a portion of the continuous surface of the load bed when the hitch ball is pivoted to an out of use position.
Such prior art retractable fifth wheel assemblies all require substantial mechanical structure to permit the retraction of the hitch ball to a non-use position wherein the cargo bed of the vehicle may be utilized in a conventional manner. Such structures are mechanically complex and not only increase the cost of the fifth wheel assemblies but also are structures which may be accidentally manipulated when the hitch ball is supposed to be in a use position so that the hitch ball may be accidentally released from its vertically elevated position thereby potentially presenting a situation where the hitch ball is not fixedly secured to its mounting assembly at a point in time when a load is being placed thereon. Such a situation could lead to a shifting of the load with respect to the towing vehicle thereby causing a potentially hazardous situation which could lead to injury of the operator of the vehicle or another vehicle passing in close proximity to either the towing or trailing vehicle. For instance, in the structure disclosed in Gibbany, et al, an accidental displacement or failure of the hydraulic system would lead to the automatic release of the hitch ball under the influence of the spring associated with the support assembly for the hitch ball. In the reference to Mann, et al, the inadvertent operation of the crank assembly which operates the gear mechanism could also lead to the retraction of the hitch ball at a point in time when the hitch ball is supposed to be locked in its extended use position. In the patent to Hamilton, if a load were to encounter the pivotable plate which retains the hitch ball in position while the hitch ball is in use, the hitch ball could swing toward a retracted position thereby shifting the load associated with the trailer with respect to the hitch ball assembly.
In view of the foregoing, it is necessary to provide a fifth wheel trailer hitch assembly for use with vehicles having flat cargo beds wherein the hitch ball may be safely secured in a vertical use position when a trailing vehicle is connected thereto but which also permits the hitch ball to be retained with the vehicle in an out of use position in such a manner that the load bed of the vehicle may be utilized in its conventional manner.